Photographic products comprising an opacifying agent in association with a reflecting agent

ABSTRACT

Film assemblies in the nature of a self-developing film which comprise a photosensitive element including an opaque support carrying photosensitive silver halide having associated diffusion transfer process dye image-providing material; an image-receiving element including a transparent support carrying a diffusion transfer image-receiving layer and a reflecting layer; rupturable container means retaining a fluid processing composition for distribution between the photosensitive and the image-receiving elements; and including opacifying agent disposed in the fluid processing composition and/or integral with or as a layer on the surface of the image receiving element&#39;&#39;s reflecting layer opposite the transparent support, for processing external a camera in which the film assembly is exposed and adapted to provide a color reflection print as a function of the film unit&#39;&#39;s photoexposure. Subsequent to exposure, the film unit is specifically adapted to be withdrawn from the camera between pressure-applying members which effect release of the fluid processing composition for production of the dye transfer image. During and subsequent to processing, formation of the color reflection print may be viewed through the image-receiving element&#39;&#39;s transparent support against the background provided by the element&#39;&#39;s reflection layer and the reflection layer, taken together with the opacifying agent, is specifically adapted to protect the photosensitive silver halide from exposure during processing in the presence of radiation incident on the viewing surface.

United States Patent 1191 Land [ Dec. 11, 1973 PHOTOGRAPIIIC PRODUCTSCOMPRISING AN OPACIFYING AGENT IN ASSOCIATION WITH A REFLECTING AGENT[75] Inventor: Edwin H. Land, Cambridge, Mass.

[73] Assigneez' Polaroid Corporation, Cambridge,

Mass.

22 Filed: Oct. 22, 1971 21 Appl. No.: 191,941

[52] US. Cl. 96/77, 96/76 C [51] Int. Cl. G03c 1/48, G03c 5/54, G0307/00 [58] Field of Search 96/3, 77, 29 D [56] References Cited UNITEDSTATES PATENTS 3,415,645 12/1968 Land 96/3 3,647,437 3/1972 Land 96/3Primary Examiner-Norman G. Torchin Assistant ExaminerAlfonso T. SuroPico Attorney-Robert M. Ford et al.

[57] ABSTRACT Film assemblies in the nature of a self developing filmwhich comprise a photosensitive element including an opaque supportcarrying photosensitive silver halide having associated diffusiontransfer process dye image-providing material; an image-receivingelement including a transparent support carrying a diffusion transferimage-receiving layer and a reflecting layer; rupturable container meansretaining a fluid processing composition for distribution between thephotosensitive and the image-receiving elements; and includingopacifying agent disposed in the fluid processing composition and/orintegral with or as a layer on the surface of the image receivingelement's reflecting layer opposite the transparent support. forprocessing external a camera in which the film assembly is exposed andadapted to provide a color reflection print as a function of the filmunits photoexposure.

Subsequent to exposure, the film unit is specifically adapted to bewithdrawn from the camera between pressure-applying members which effectrelease of the fluid processing composition for production of the dyetransfer image. During and subsequent to processing, formation of thecolor reflection print may be viewed through the image-receivingelements transparent support against the background. provided by theelements reflection layer and the reflection layer, taken together withthe opacifying agent, is specifically adapted to protect thephotosensitive silver halide from exposure during processing in thepresence of radiation incident on the viewing surface.

15 Claims, 9 Drawing Figures PATENTEDHEBI 1 5 3.778.271

SHEEI 1 OF 4 INVENTOR. EDWIN LAND M W6. gm

ATTORNEYS PATENTED DEC] 1 I975 MEI30F4 MGE INVENTOR. EDWIN H. LAND @Jwwn mm! M mm! W 77?. you! ATTORNEYS mm mm PHOTOGRAPHIC PRODUCTS COMPRISINGAN OPACIFYING AGENT IN ASSOCIATION WITH A REFLECTING AGENT BACKGROUND OFTHE INVENTION The present invention is concerned with photo graphic filmunits, particularly adapted for employment in a photographic film packor film magazine of the type shown in US. Pat. No. 3,080,805, issuedMar. 12, 1963, in the name of Joel A. Hamilton, comprising a container,at least one film unit mounted for exposure within the container and aclosure element for preventing the admission of light into thecontainer. As disclosed in that patent, each film unit includes, incombination, a first photosensitive element positioned for exposurewithin the container; a second nonphotosensitive element, preferably aprint-receiving element, adapted to be superposed with thephotosensitive element during withdrawal of the film unit from thecontainer, following exposure thereof; and frangible container meansparticularly adapted to releasably retain a fluid processing compositionfor distribution between the superposed photosensitive andprint-receiving elements subsequent to photoexposure of the film unit.

In general, the film pack or container includes an exposure apertureadapted to permit exposure of the photosensitive element; a removableclosure element located across the exposure aperture; at least one filmunit; and an opening permitting withdrawal of the closure element andfilm units from the container successively through this opening. Theclosure element and each film unit includes a leader adapted to projectfrom the film pack through the opening whereby to provide means forselectively withdrawing the closureelement, or a film unit, from thefilm pack into contact, and in engagement, with means adapted to provideindividual distribution of the retained fluid processing composition,between superposed photosensitive and nonphotosensitive elements.

Film packs of this type are intended to be employed in photographicapparatus, such as a camera, which include means for maintaining a filmpack in position for exposure, means for selectively exposing thephotosensitive element of successive film units of the pack, and meansfor engaging each film unit during withdrawal from the pack, subsequentto photoexposure, and distributing the retained processing fluidbetween, and in contact with, the contiguous photosensitive andprintreceiving elements of the film unit, for effecting photographicdiffusion transfer processing of the respective, photoexposed film unit.Processing of each film unit may thus be effected manually by grasping aleader attached to the film unit and withdrawing the leader and filmunit from both the pack and the camera.

In photographic diffusion transfer processing, the photosensitive sheetelement is normally first exposed and then biased into superposedrelationship with a second sheet element, which is, in general,photographically inert and aids in the controlled distribution of theprocessing composition. The photosensitive element may contain anintegral print-receiving stratum or the second sheet element maycomprise a transfer imagereceiving element. The contiguous sheetelements are moved relative to, and between, a pair of suitably opposedmembers such as gapped parallel pressure rollers or platens. Applicationof pressure to the frangible fluid-retaining means effects controlledrupture thereof and predetermined unidirectional distribution of itsprocessing composition contents between, and in contact with, theopposed surfaces of the superposed elements, Subsequent to transferprocessing, the image-carrying area of the print-receiving element isgenerally separated from the laminate.

In general, color photographic reproduction may be provided by diffusiontransfer processing such as exposing a photoresponsive material, forexample, photosensitive silver halide layer having associated therewithdye image-providing material which is processing composition diffusible,as a function ofexposure of its associated photosensitive silver halide,such as the dye image-providing materials disclosed in US. Pat. Nos.

3,087,817; etc., as adapted to provide imagewise differential transferof dye image-providing material to a contiguous image-receptive elementproviding dye image formation to such element as a function of thepoint-to-point degree of silver halide layer photo- SUMMARY OF THEINVENTION The present invention is directed to a film assembly forproducing color reflection prints employing a film pack or magazine typeunit. The assembly is composed of a first sheet element comprising aphotosensitive structure including, in essence, an opaque supportcarrying a photoresponsive material, such as photosensitive silverhalide crystals having associated therewith a dye image-providingmaterial which is processing composition diffusible as a function of thephotoexposure of associated photosensitive silver halide; a second sheetelement comprising, in essence, a transparent support carrying, inorder, a layer adapted to receive the image formed as a function ofphoto-exposure of the photoresponsive material and a dye imageprovidingmaterial permeable visible light-reflecting layer, adapted to besuperposed over the exposure surface of the photosensitive element, withthe respective supports outermost, subsequent to exposure of thephotoresponsive material; frangible fluid retaining means adapted todischarge processing composition retained therein between the first andsecond sheet elements; means including a leader for coupling the firstsheet element and the second sheet element and withdrawing same insuperposed relationship from the exposure apparatus; and an opacifyingagent disposed integral with and or/ contiguous the surface of thereflecting layer opposite the transparent support and/or in theprocessing composition in a concentration effective, taken together withthe reflecting layer, to prevent photoexposure of the first sheetelements photoresponsive material by radiation aetinic thereto incidenton the second sheet element in superposed relationship with the firstsheet elements exposure surface.

The described film assembly is first exposed in an apparatus such as ahand-held camera by radiation incident on the exposure surface of thefirst sheet element and then biased into superposed relationship withthe second sheet element to permit removal from the apparatus andprocessing of the exposed photoresponsive material under ambient lightconditions external to the exposure device. Substantiallycontemporaneous with the removal of the film assembly from the camera,the frangible container is ruptured, discharging its contentsintermediate the opposed surfaces of the first and second sheetelements, and the leader and fluid retaining means are thereafteroptionally detached from association with the remainder of the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary perspectiveview of a photographic film unit embodying the invention;

FIG. 2 is a plan view of the film unit of FIG. 1;

FIG. 3 is a perspective view of a film pack comprising an assemblage offilm units;

FIG. 4 is a longitudinal sectional view taken substantially midwaybetween the sides of the film pack of FIG.

FIG. 5 is a diagrammatic sectional view taken sub stantially midwaybetween the sides of the film pack showing one film unit with thecomponents thereof spaced apart to more clearly illustrate theconstruction and arrangement of the film unit;

FIG. 6 is an elevational view, partially in section, of photographicapparatus in the form ofa camera for employing film units embodying theinvention;

FIG. 7 is a fragmentary sectional view, similar to FIG. 6, illustratinginitiation of an initial passage of one film unit between a pair ofopposed pressure-applying rolls during removal of the film unit from thecamera apparatus of FIG. 6, subsequent to photoexposure;

FIG. 8 is a fragmentary sectional view, similar to FIG. 7, illustratingfurther passage of the film unit between the pair of opposed pressurerolls, rupture of the frangible container and distribution of its fluidprocessing composition contents between, and in contact with, theopposed surfaces of the superposed sheet elements of the film unit; and

FIG. 9 is a fragmentary sectional view, similar to FIG. 8, illustratingcompletion of the passage of the film unit between the pair of opposedpressure rolls, the laminate formed by distribution of the fluidprocessing composition between the superposed sheet elements.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the presentinvention, the preferred form of the film assemblage for the productionofa dye reflection print comprises a photosensitive film unitspecifically adapted to be processed in the presence of ambientradiation and the dye reflection print image to be viewed during andsubsequent to processing without separation of film unit componentsincluding a first photosensitive sheet element comprising an opaquesupport carrying on one surface a photoresponsive material havingassociated therewith a dye imageproviding material, which is processingcomposition diffusible as a function of the photoexposure of associatedphotoresponsive material adapted to be exposed by incident actinicradiation to produce photographic information recordation; a second dyeimage receptive sheet element comprising a transparent support carryingon one surface, in order, an image-receiving layer adapted to receive bydiffusion transfer processing an image as a function of the exposure ofthe photoresponsive material and a dye image-providing materialpermeable visible light-reflecting layer, adapted to be biased intosuperposed relationship contiguous the exposure surface of the firstphotosensitive sheet element subsequent to exposure; a rupturablecontainer containing a fluid agent for reacting with the exposedphotoresponsive material for forming the image in the image-receptivelayer; means including a leader for coupling the photosensitive unit andthe second opaque sheet and for withdrawing the unit and the sheet insuperposition from a film pack or magazine; and opacifying agentdisposed integral with and/or contiguous the surface of the reflectinglayer opposite the transparent support and/or in the fluid agent in aconcentration effective, taken together with the reflecting layer, toprevent exposure of the first sheet elements photoresponsive material byradiation actinic thereto incident on the transparent support of thesecond sheet element in superposed relationship with the first sheetelement in the processing mode.

The preferred form or film pack or magazine embodying the designatedfilm units comprises a plurality of the film assemblies, each adapted tobe individually exposed in a camera, enclosed in a light-proof containerwhich allows the film units to be sequentially exposed. The containerincludes a forward wall having an exposure aperture therein and anopening in one end through which film assemblies can be individuallywithdrawn with the photosensitive and second sheet elements of each filmunit in superposed relation. The photosensitive film units arepositioned together within the container underlying the exposureaperture with the exposure surface of the first photosensitive sheetelement uppermost and the second image-receptive sheet elements arearranged together, apart from, and behind the photosensitive elementsadjacent the opening through which the film units are withdrawn so thatfollowing the exposure of the photosensitive sheet element of each filmunit, the photosensitive element is moved, by drawing on the leader ofthe film unit, into superposition with the second element of the filmunit and the film unit is then withdrawn from the container through theopening. The film pack is initially provided with a cover element orsheet mounted within the container and extending across the exposureaperture for closing the aperture against the admission of light. Thecover element also includes a leader extending from the containerthrough the opening and being removable therethrough.

The film pack is employed by being positioned in a camera, including apair of juxtaposed pressureapplying members, with the opening locatedadjacent the pressure-applying members and the exposure aperturedisposed approximately in the exposure plane of the camera. The leadersof the film units and cover element extend from the pack and from thecamera where the last-mentioned leader may be grasped for withdrawingthe cover element from the pack and camera to allow the photosensitiveelements of the pack to be exposed. After the photosensitive elements ofeach successive film unit is exposed, that film unit is then withdrawnfrom the container and camera between the pressure-applying members bywithdrawing the leader of the first film unit and of successive filmunits from the container and camera.

By employing the film assemblages of the present invention, colorreflection prints can be provided employing photographic diffusiontransfer processing effected external the camera in which the film unitswere subjected to exposure and in the presence of ambient radiation.

DETAILED DESCRIPTION OF THE DRAWINGS Reference is now made to FIGS. 1through 9 of the drawings wherein there are illustrated film units andan assemblage of film units in the form of a film pack. Each film unitdesignated 10 comprises a generally rectangular photosensitive colorsheet element 11, comprising an opaque support carrying on one surface aphotosensitive silver halide layer and a second imagereceptive sheetelement 18 adapted to be superposed on exposure surface 19 of theelement opposite the first opaque support. Photosensitive sheet element11 possesses a first leading section 20 approximately equal in width toelement 11 and provides means for mounting rupturable container 21 ofprocessing fluid, and includes a leading end section 22. Image-receptivesheet element 18 is approximately equal in width to element 11 andincludes a tapered leading end section 23 approximately equal indimensions to tapered end section 22 of sheet 11. Side guides 24 aresecured to the lateral edges of sheet 18 coextensive the length ofelement 11 whereby to provide a gap control between sheet 18 and element11 during processing, and the lateral boundaries of the element 11 maybe secured to the corresponding lateral boundaries of sheet 18 at therespective interface therebetween in any analagous manner as tofacilitate retention of the processing fluid intermediate sheet 18 andelement 11.

Tapered end sections 22 and 23 cooperate to define the leading endsection of film unit 10 to be advanced between the pressure-applyingmembers as further defined hereinafter.

The length of sheets 11 and 18 is substantially equal and by virtue ofthis arrangement, the sheets are readily superposed in registeredrelation during the processing of the film unit. A trailing end section25 of sheet 11 extends beyond the trailing edge 26 of element 11 tocoact with trailing end section 27 of sheet 18 to trap any excessprocessing fluid which may be carried beyond the trailing ends of thephotosensitive element 11 during distribution of the processing fluid.Distribution of the processing fluid, as noted, is effected by advancingsheets 11 and 18 and container 21 of processing fluid, the former insuperposition, relative to and between a pair of juxtaposedpressure-applying members 29 and 30. The pressure-applying members,e.g., opposed suitably gapped rolls, apply compressive pressure to thesheets progressively, commencing in the area of the container, to causethe ejection of the fluid contents of the container between and incontact with the opposed surfaces of the sheet 18 and element 11. To aidin trapping of excess fluid, spacing members 31 may be provided ontrailing end section 27 adjacent the margins thereof for spacing apartthe pressure-applying members to provide a gap between trailing endsection 25 of sheet 11 and trailing end section 27 of sheet 18 in whichany excess processing fluid may be collected and retained.

As disclosed in the drawings, there may be attached to the leading edgeof photosensitive laminate 16 a leader sheet 12 having a first section20 in which the leader sheet 12 is coupled with the photosensitivelaminate. First section 20 is approximately equal in width to thephotosensitive laminate and provides means for mounting rupturablecontainer 21. As shown, leader sheet 12 includes tapered end section 22.Imagereceiving laminate 17 is shown mounted on a carrier sheet 13 havingan intermediate section 14 approximately equal in width to theimage-receiving laminate and having a generally rectangular opening 15therein defining the area of the image-receiving laminate in which imageformation occurs. Carrier sheet 13 includes a leading end section 23having a tapered end portion 28 similar to tapered end section 22 andsecured thereto intermediate the ends of tapered end section 22 andtapered end portion 28 of leading end section 23. As shown, tapered endsection 22 and end portion 28 cooperate to define the leading endsection of the film unit which is advanced between the pressureapplyingmembers 29 and 30. Where desired, intermediate section 14 of carriersheet 13 may be secured to the external surface of image-receivinglaminate 17 so that portions of the intermediate section bordering onopening 15 may provide a mask. for defining image area.

The length of leader sheet 12 between the leading edge of photosensitivelaminate 16 and the point of attachment of leader sheet 12 to carriersheet 13 is substantially equal to the length of carrier sheet 13between its point of attachment to the leader sheet and the leading edgeof image-receiving laminate 17. By virtue of this arrangement,photosensitive laminate 16 and image-receptive laminate 17 aresuperposed in registered relation during rocessing of film unit 10. Asshown, a trailer sheet 25 is provided secured to the trailing edge ofphotosensitive laminate 16 for cooperation with the opposed trailing endsection 27 of carrier sheet 13 to trap excess processing, fluid whichmay be transported beyond the trailing ends of the photosensitive andimage-receptive laminates during distribution of processing composition.

The rupturable container is of the type shown and described in US. Pat.Nos. 2,543,181; 2,634,886; 2,653,732; 2,674,532; 2,702,146; 2,723,051;2,750,075; 3,056,491; and 3,056,492, and may comprise a rectangularblank of fluid-and air-impervious sheet material folded longitudinallyupon itself to form two walls which are sealed to one another along thelongitudinal and end margins to form a cavity in which the processingfluid is contained. Longitudinal marginal seal 32 is made weaker thanthe end seal so as to become unsealed in response to hydraulic pressuregenerated within the fluid contents of the container by the applicationof compressive pressure to the walls of the container. Container 21 ismounted on sheet 11 with the longitudinal marginal seal directed towardthe leading edge 33 of element 11. Bib sheet 34 is secured to sheet 11at lateral edges 35 and 36, center area 37, trailing edge 38 ofcontainer 21, and leading edge 33 of element 11, and facilitatesrestricted unidirectional flow of fluid contents 39 upon compressiverupture of container 21. Edge 40 of bib sheet 34 extends beneath leadingedge 33 of element 11. Thus, the flow of fluid contents 39 fromcontainer 21 is directed beneath bib sheet 34 and distributedintermediate element 11 and sheet 18.

For details concerning the composition of the fluid and materials usefulin forming the color image, reference may be had to the aforementionedU.S. Pats.

A film pack or assemblage of film units is shown in FIGS. 3 and 4 of thedrawings. This film pack, designated 41, comprises a generallyparallelepiped-shaped container or box 42 for holding and enclosing aplurality of film units 10. Container 42 is shown as comprising twosections, including a forward section having a forward wall 43, sidewalls 44, a trailing end wall 45, and a leading end wall 46. Forwardwall 43 is provided with a generally rectangular exposure aperture 47for transmitting light for exposing the photosensitive sheets of filmunits carried within the container. Leading end wall 46 comprises only apartial wall, i.e., it does not extend rearwardly to the same extent asthe side walls, which cooperates with the rear section of the containerto provide a passage 48 at the leading end of the container throughwhich film units 10 carried by the container are withdrawn. The rearsection of the container comprises a rear wall 49 secured to side walls44 and formed preferably of a resilient sheet metal.

The arrangement of each film unit within container 41 is illustrated inFIGS. 1 and 5; and the arrangement of a plurality of film units (two areshown) is illustrated in FIG. 4. Each film unit is arranged with thephotosensitive and second sheets in overlying relation with thephotosensitive layer of element 11 facing outward and with thereflecting layer of image-receptive sheet 18 which is superposedtherewith, during processing, facing inwardly in the same direction.Leading end section 20 of sheet 11 is folded or curved adjacent theleading edge 33 of element 11 intermediate that edge and container 21,and leading end section 23 of sheet 18 is similarly folded adjacent theleading edge of the sheet so that leading portions of leading endsections 20 and 23 interconnect sheet 11 and 18 in the stated spacialarrangement upon superpositioning of the sheets; and trailing endsection 25 of sheet 11 is disposed adjacent, respectively, trailing endsection 27 of sheet 18. The film pack is provided with a generally flat,rectangular pressure plate 50 located intermediate sheet 1 1 and theother portions of the film unit for supporting element 11 against theinner surface of forward wall 43 in position for exposure throughaperture 47. Pressure plate 50 includes a rolled end section 51 aroundwhich extends the curved portion of sheet 16. Rolled end section 51 isprovided for guiding photosensitive element 11 around the end of thepressure plate in a manner to be described hereinafter. The majorportion of first section 20 of sheet 11 rupturable container 21 mountedthereon, tapered section 22 and the leading tapered end section 23 ofsheet 18 are located behind pressure plate 50 between the latter andsheet 18. Pressure plate 50 is provided with lateral flanges 52 disposedadjacent side walls 44 of the container. Rear wall 49 of the housing isprovided with springs 53 formed from the rear wall and biased inwardlyfor engaging lateral flanges 52 and biasing pressure plate 50 towardforward wall 43 to retain element 11 in position for exposure. Rear wall49 is also provided with a U-shaped opening or enlarged notch 54 in theend portion thereof adjacent opening 48 the purpose of opening 48 to befurther described hereinafter.

The means for withdrawing each film unit 10 from container 41 withelement 11 and sheet 18 in superposition and advancing tapered endsections 22 and 23 between a pair of pressure-applying members comprisesa relatively narrow elongated leader 55 secured at the trailing end ofthe leader to tapered end section 22 of sheet 1 1 preceding the point ofattachment of the tapered end section 22 to tapered end portion 23 ofsheet 18. Leader 55 is of substantially uniform width throughout itslength. The areas of adherence of leader 55 to tapered end section 22extend substantially in the direction of movement of the leader, andcomprise any suitable adhesive material which will form a bondpreferably at least equal in strength to the sheet materials (paper)comprising the leader and tapered end section, sufiicient in resistanceto the application of tension, in a direction of the plane of taperedend section 22, to prevent shearing. The adhesive bond is such that theapplication of a suitable shearing force to leader 55, effective byapplying tension to the leader in a direction at an angle from the planeof tapered end section 22, causes leader 55 to disengage from contactwith tapered end section 22. By virtue of this construction, as long asthe leader and film unit coupled therewith are being moved inapproximately the same direction, then the leader is in tension and doesnot fail. However, when the direction of movement of leader 55 andtapered end section 22 diverges sufficiently (as shown in FIG. 7), thetrailing end section of the leader is subjected to a shearing forcewhich causes the leader to tear and thereby become detached from taperedend section 22.

Leader 55 extends from container 41 through opening 48 therein and, whendrawn from the container, advances element 11 around rolled end section51 of pressure plate 50 into superposition with a second sheet 18 andthen advances the two sheets in superposition within the containertowards opening 48. As leader 55 commences to advance towards opening48, tapered end section 22 of sheet 11 is required to commence rollingupon itself toward the opening in response to movement of tapered endsection 22 of sheet 11 toward the same opening. It is for this reasonthat section 22 and portion 23 are tapered, since this provides for theWeakest portion of end portion 22 in the area where the end portion isrequired to commence rolling. Means may also be provided for preventingmovement of elements underlying the foremost element 11 as the latter ismoved from exposure position around the end of the pressure plate.

Film pack 41 is provided with means for initially sealing aperture 47against the admission of light until the pack has been loaded into thecamera in which it is to be employed. This light-sealing means comprisesa cover sheet 56 (double) of a light-impervious material located betweenthe foremost photosensitive sheet and forward wall 43 across opening 47.Cover sheet 56 extends around the curved end of the pressure platebehind the latter to a position against rear wall 49 with the leadingend of the cover sheet locatediadjacent passage 48. An elongated leadersection 108, similar to leader 55, provides means for withdrawing coversheet 56 from container 41 after the container has been loaded into acamera.

The film units incorporating the invention and comprising film pack 41are adapted to; be employed in photo-graphic apparatus such as ahand-held camera 57, illustrated in FIGS. 6 through 9 of the drawings.Camera 57 comprises a housing including a forward section 58 having aforward wall 59 with a recessed or reentrant section 60 and an aperture61 in the reentrant section for transmitting light for exposing element11 of a film pack positioned for exposure within the camera. A hingeddoor 62 is provided for covering recessed section 60 and for mounting alens and shutter assembly 63, the latter being connected to recessedsection 60 by a collapsible bellows 64 secured at one end to the lensand shutter assembly and secured at its other end to the recessedsection in surrounding relation to aperture 61, the former comprising animagereversing optical system adapted to rectify geometric transferimage reversal which is resultant from exposure and processing of thefilm unit by reason of the units structural parameters. In lieu of door62, lens and shutter assembly 63 and bellows 64, the camera housing canbe constructed in the form ofa camera back or film pack adaptor intendedto be mounted on or coupled with a camera or other photographic exposuredevice.

The camera housing includes a rear section 65 having a rear wall 66 andside walls 67 cooperating with forward housing section 58 to provide achamber 68 to the rear of forward wall 59 and aperture 61 for containingthe film pack in position for exposure through aperture 61. Film pack 41is mounted within chamber 68 with the wall of the pack located againstthe rear surface of reentrant section 60 and with aperture 47 in theforward wall of the pack aligned with aperture 61. Rear housing section65 is preferably pivotably secured to forward housing section 58adjacent one end of the housing, herein shown and designated forpurposes of description as the upper end, by a hinge which permits thetwo housing sections to be moved apart from one another to allow loadingof a film pack into chamber 68. The camera housing includes a lower endwall comprising end wall 69 on forward housing section 58 and anotherend wall 70 on rear housing section 58. A film withdrawal passage 71 isprovided in lower end wall of the housing to permit withdrawal of a filmunit from the housing. Suitable latch means (not shown) of aconventional type are also provided in the lower portion of the housingfor retaining the two housing sections together in the closed oroperative position shown in the drawmgs.

Camera 57 includes a pair of juxtaposed pressureapplying members in theform of pressure-applying rolls 29 and 30 within chamber 68 adjacentfilm withdrawal passage 71. Pressure-applying rolls 29 and 30 aremounted for pivotal movement with their axes substantially in a commonplane, and resilient means are provided for biasing the rolls toward oneanother into juxtaposition so as to apply compressive pressure to a filmunit during movement thereof between the rolls. The pressure-applyingrolls cooperate to form a convergent (and divergent) passage throughwhich the film unit is moved for effecting the processing of the filmunit, and this passage between the pressure-applying rolls is located insubstantial alignment with withdrawal passage 71. In the arrangement ofthe pressureapplying rolls shown in the drawings, both rolls are mountedon rear housing section 65 so that when the housing sections are pivotedapart from one another, an assemblage of film units may be loaded intothe camera with the leaders thereof extending from the camera past andto one side (forward) of the pressure applying rolls. Portions of endwalls 69 and 70 cooperate to define an opening 82 between the forwardand rear housing sections through which the leaders extend from thecamera housing.

Camera 57 includes means for guiding the tapered end section of filmunit 10 between pressure-applying rolls 29 and 30 in response towithdrawal movement of leader 55 past roll 29 to the front thereof andthrough opening 71. In the form shown in FIG. 6, this guide meanscomprises a guide bar 75 mounted on rear housing section 65 closelyadjacent roll 29 and having a substantially straight guiding edgeextending from side to side of the camera housing and lyingsubstantially in a plane through the convergent passage betweenpressure-applying rolls 29 and 30, i.e., tangent to the rolls. Section76 of guide bar 75, comprising the forward edge of the guide bar islocated with its forward edge approximately in line with the forwardmostportion of roll 29, and guide bar 75 may be provided with facing endsurfaces spaced from one another by a distance slightly greater than thewidth of leader 55. A guide plate 78, approximately equal in length tothe width of leader 55, including facing end sections 79 spaced from oneanother by a distance slightly greater than the width of leader 55, ismounted on forward housing section 58, and extends toward the rear ofthe camera adjacent guide bar 75 at its forwardmost extremity 80. Therearmost edge of guide plate: 78 may be curved, where desired. Guide bar75, facing end sections 79, and guide plate 78 cooperate with oneanother to define a guide passage extending generally in a directiontoward end wall 70 of the camera and having a width, measured from sideto side of the camera, just slightly greater than the width of leader55, so that the leader may be moved through passage 81. It will be notedthat tapered end section 22, at the leading edge thereof, is wider thanleader 55 so that tapered end section 22 is unable to enter passage 81.Facing surfaces 79 of guide plate 78 function to guide tapered endsection 22 of the film unit into the convergent passage betweenpressureapplying rolls 29 and 30.

In the loading and operation of the camera, the forward and rear housingsections are pivoted apart from one another and a film pack 41 ispositioned within the forward housing section 58 with the forward wall43 of pack 41 resting against section of the forward wall 59 of forwardhousing section 58, and with leaders 55 and leader 108 projecting fromthe pack extending across and to the rear of guide plate 78 and end wall69. Rear housing section is then pivoted into the operative positionshown, causing the intermediate section 82 of guide bar 75 to engage theleaders displacing them forwardly so that they extend. through passage81 toward the forward wall of the camera, past pressureapplying roll 29and through opening 82 in end walls 69 and 70. As a leader 55 iswithdrawn from the camera through opening 71, the tapered end section iswithdrawn from the pack and, being unable to enter passage 81, is guidedby the guide bar, guide members and guide plate into the convergentpassage between the pressure-applying rolls.

Film withdrawal passage 71, in the lower end wall of the camera housing,is at least equal in width to the width of the film unit, whereaspassage 81 need be of a width only sufficient to allow the passage ofleaders 55. It is desirable to allow only one leader at a time toproject from the camera where the leader may be grasped; and this isdesirable to prevent the operator from accidentally pulling the wrongleader, or pulling more than one leader at a time. For this purpose, endwall 70 is provided with a recess, designated 84, adjacent passage 81for holding the leading end sections of leaders 55. The leading endsections, designated 85, of leaders 55, are folded back upon themselvesand each leading end section is detachably adhered to the leader of thepreceding film unit, with the leading end section 85 of the first (to beexposed) film unit being attached to leader 56. The folded leading endsections 85 of leaders 55 are contained within recess 84 which isprovided with a deplaceable guide bar element 75. As leader 56 or aleader 55 is withdrawn through opening 71, the the leader is attached tothe tapered end section and results in separation of the leader at theseareas.

Application of withdrawing force on tapered end section 22, advancingelement 11, second sheet 18 and container 21 between pressure-applyingrolls 29 and 30 to the position shown in FIG. 8 provides rupture of thelongitudinal marginal seal 32 of container 21 and unidirectional releaseof fluid processing composition 39 between and in contact with opposedleading end section 85 of the next succeeding leader 55 is unfolded andwithdrawn from recess 84 where the leading end section may be graspedfor pulling the leader from the camera. By virtue of this arrangement,only one leader at a time extends outside of recess 84 in position to beengaged and withdrawn.

In the operation of the film unit of the invention, leader 55 is pulledfrom the camera advancing tapered end section 22 and tapered end portion23 between pressure-applying rolls 29 and 30 to the position shown inFIG. 7 at which leader 55 extends from its point of attachment totapered end section 22 at almost a right angle from the plane of thetapered end section. At this position, the leading end of tapered endsection 22 projects through passage 71 a sufficient distance to permitthe tapered end section to be grasped, and the application of acontinued pulling force on leader 55 results in the exertion of ashearing force to leader 55 at the areas where it is secured to thesurfaces of photosensitive element 11 and image-receptive element 16.

Continued withdrawing force on film unit 10 between pressure-applyingrolls 29 and 30 to the position shown in FIG. 9 provides interengagementunder pressure between sheet 18 and exposure surface 19 ofphotosensitive element 11, and sheet 18 will be maintained in superposedrelationship with element 11 during and subsequent to processingexternal camera 57, although optionally subject to separation, and theresultant dye transfer image viewed in image-receiving layer 104 duringand subsequent to its formation through transparent support 107.

Where desired trailing end section 27 of sheet 18 and trailing endsection 25 of sheet 11, for example, may be secured together by positiveengaging means adapted to insure retention of processing compositionoverrun disposed intermediate the sections thus preventing escapeexternal the film unit boundaries.

The positive engaging means employed should be simple and inexpensive tofabricate, so that it does not add appreciably to the cost of the filmunit, and it should be easy to assemble and employ in order tocontribute in a practical manner to the efiicient operation of the filmunit, and film pack and camera employing same. As examples of suchengaging or lock closure means, mention may be made of moisturesensitive adhesives activatable upon contact with the fluid processingcomposition; self-adhering adhesives coated on the trailingprospectively opposed surface of each sheet element; and engagingmembers such as shaped, extruded plastic interlocking elements having apluality of, preferably resilient, interlocking tongues and groovesmounted on the distal opposed surfaces of each sheet element; a maleengaging member mounted on the distal surface of one sheet element and afemale engaging member mounted on the distal prospectively opposedsurface of the other sheet element and may comprise, respectively,tongue and groove or ball and socket construction, and preferablypossesses at least one resilient component member adapted for frictionalretention upon engagement with the second member; a plurality ofpolymeric hooks, for example, nylon hooks, positioned on the trailingedge of one sheet element and a plurality of filamentary loops on thetrailing edge of the second sheet element such as the closure materialssold by Velcro Corporation, Manchester, NH. etc.

It will be recognized that, as desired, the engaging means may extend,in whole or in part, in continuous or discontinuous fashion, lengthwisethe trailing edge of edges retaining same.

In a preferred embodiment of the present invention, the means forinterposing the processing composition selected intermediate thereception layer and the silver halide layer comprises a rupturablecontainer retaining a processing composition comprising the solvent andpH concentrations required fixedly positioned and extending transverse aleading edge section of the sheet elements to effect, upon applicationof compressive pressure, discharge of the processing compositionintermediate the reception layer and the photosensitive silver halidelayer next adjacent. In such embodiment the opacifying agent ispreferably disposed within the processing composition, as retained inthe rupturable container, for distribution as a component of suchcomposition intermediate the reception and silver halide layers,subsequent to selective exposure of the film unit.

Multicolor images may be obtained using color image-forming componentsin the diffusion transfer process of the present invention by severaltechniques. On such technique contemplates obtaining multicolor transferimages utilizing, for example, dye developers as dye image-providingmaterials by employment of an integral multilayer photosensitiveelement, such as is disclosed in aforementioned U. S. Pat. No. 2,983,606wherein at least two selectively sensitized photosensitive strata,superposed on a single support, are processed, simultaneously andwithout separation, with a single, common image-receiving layer. Asuitable arrangement of this type comprises the opaque support carryinga red-sensitive silver halide stratum, a greensensitive silver halidestratum and a blue-sensitive silver halide stratum, said emulsionshaving associated therewith, respectively, for example, a cyan dyedeveloper, a magenta dye developer and a yellow dye developer. The dyedeveloper may be utilized in the silver halide stratum, for example, inthe form of particles, or it may be employed as a layer behind theappropriate silver halide strata. Each set of silver halide strata andassociated dye developer strata are disclosed to be optionally separatedfrom other sets by suitable interlayers, for example, by a layer ofgelatin or polyvinyl alcohol. In certain instances, it may be desirableto incorporate a yellow filter in front of the green-sensitive emulsionand such yellow filter may be incorporated in an interlayer. However,where desirable, a yellow dye developer of the appropriate sepectralcharacteristics and present in a state capable of functioning as ayellow filter may be employed. In such instances, a separate yellowfilter may be omitted.

In a preferred embodiment of the present invention, the film unit isspecifically adapted to provide for the production of a multicolor dyetransfer image and the photosensitive laminate comprises, in order ofessential layers, the dimensionally stable opaque layer; at least twoselectively sensitized silver halide strata each having dyeimage-providing material .of predetermined color associated therewith,for example, dye developers asdetailed above, which are soluble anddiffusible in processing composition as a function of the point-topointdegree of exposure of the respective associated silver halide stratum.In such instance the imagereceptive sheet element will be a polymericlayer dyeable by the dye image-providing materials and a dimensionallystable transparent layer.

In view of the fact that the preferred dye imageproviding materialscomprise dyes which are silver halide developing agents, as statedabove, for purposes of simplicity and clarity, the present inventionwill be further described hereinafter in terms of such dyes, withoutlimitation of the invention to the illustrative dyes denoted, and, inaddition the photographic film unit structure will be detailedhereinafter employing the last-mentioned preferred structuralembodiment, without limitation of the invention to the preferredstructure denoted.

The dye developers, as noted above, are compounds which contain, in thesame molecule, both the chromophoric system of a dye and also a silverhalide developing function. Bya silver halide developing function ismeant a grouping adapted to develop exposed silver halide. A preferredsilver halide development function is a hydroquinonyl group. Othersuitable developing functions include ortho-dihydroxyphenyl and orthoandpara-amino substituted hydroxyphenyl groups. In general, the developmentfunction includes a benzenoid developing function, that is, an aromaticdeveloping group which forms quinonoid or quinone substances whenoxidized.

The dye developers are preferably selected for their ability to providecolorsthat are useful in carrying out subtractive color photography,that is, the previously mentioned cyan, magenta and yellow. The dyedevelopers employed may be incorporated in the respective silver halideemulsion or, in the preferred embodiment, in a separate layer behind therespective silve halide stratum. Specifically, the dye developer may,for example, be in a coating or layer behind the respective silverhalide stratum and such a layer of dye developer may be applied byuse ofa coating solution containing about 0.5 to 8 percent, by weight, of therespective dye developer distributed in a film-forming natural, orsynthetic, polymer, for example, gelatin, polyvinyl alcohol, and thelike, adapted to be permeated bythe chosen diffusion transfer fluidprocessing composition.

The silver halide strata comprising the multicolor photosensitivelaminate preferably possess predominant spectral sensitivity to separateregions of the spectrum and each has associated therewith a dye which isa silver halide developing agent and is, most preferably,

substantially soluble in the reduced form only at a first pI-Ipossessing, subsequent to processing, a spectral absorption rangesubstantially complementary to the predominant sensitivity range of itsassociated emulsion.

In the preferred embodiment, each of the silver halide strata, and itsassociated dye, is separated from the remaining strata, and theirassociated dye, by separate alkaline solution permeable polymericinterlayers.

In such preferred embodiment of the invention, the silver halide stratacomprises photosensitive silver halide dispersed in gelatin and areabout 0.6 to 6 microns in thickness; the dye itself is dispersed in anaqueous alkaline solution permeable polymeric binder, preferablygelatin, as a separate layer about I to 7 microns in thickness; thealkaline solution permeable polymeric interlayers, preferably gelatin,are about 1 to 5 microns in thickness; the dyeable polymeric layer istransparent and about 0.25 to 0.4 mil. in thickness; and each of thedimensionally stable opaque and transparent layers are alkaline solutionimpermeable and about 2 to 6 mils. in thickness. It will be specificallyrecognized that the relative dimensions recited above may beappropriately modified, in accordance with the desires of the operator,with respect to the specific product to be ultimately prepared.

In the preferred embodiment of the present inventionss film unit for theproduction of a multicolor transfer image, the respective silverhalide/dye developer units of the photosensitive element will be in theform of a tripack configuration which will ordinarily comprise a cyandye developerlred-sensitive emulsion unit contiguous the dimensionallystable opaque layer, the yellow dye developer/blue-sensitive emulsionunit most distant from the opaque layer and the magenta dyedeveloper/green-sensitive emulsion unitintermediate those units,recognizing that the relative order of such units may be varied inaccordance with the desires of the operator.

Referring to FIG. 5 there is shown a diagrammatic enlargedcross-sectional view of sheet elements 11 and 18 constructed inaccordance with the present invention. The film unit is shown tospecifically comprise with respect to sheet element 11 a photosensitivelaminate including, in order, dimensionally stable opaque layer 91,preferably an actinic radiationopaque flexible sheet material; cyan dyedeveloper layer 92; red-sensitive silver halide emulsion layer 93;interlayer 94; magenta dye developer layer95; greensensitive silverhalide emulsion layer 96; interlayer 97; yellow dye developer layer 98;blue-sensitive silver halide emulsion layer 99; auxiliary layer 100,which may contain an auxiliary silver halide developing agent.Image-receptive sheet laminate 101is shown to comprise, in order, opaquelayer 102; reflection layer 103; imagereceiving layer 104; spacer layer105; neutralizing layer 106; and dimensionally stable transparent layer107, preferably an actinic radiation transmissive flexible sheetmaterial.

The fluid contents of the container preferably comprise an aqueousalkaline solution having a pH and solvent concentration at which the dyedevelopers are soluble and diffusible and contains an opacifying agentpreferably in a quantity sufficient, upon distribution, effective toprovide a layer exhibiting optical transmission density 6.0 to preventexposure of photosensitive silver halide emulsion layers 93, 96 and 99by actinic radiation incident on dimensionally stable transparent layer107 during processing in the presence of such radiation and to affordimmediate viewing of dye image formation in image-receiving layer 104during and subsequent to dye transfer image formation. Accordingly, thefilm unit may be processed, subsequent to distribution of thecomposition, in the presence of such radiation, in view of the fact thatthe silver halide emulsion or emulsions of laminate are appropriatelyprotected from incident radiation, at one major surface of the opaquelayer 102 and at the remaining major surface by the dimensionally stableopaque layer 91.

The selected reflecting agent providing reflecting layer 103 should beone providing image formed in the dyeable polymeric layer. In general,while substantially any reflecting agent may be employed, it ispreferred that a reflecting agent be selected that will not interferewith the color integrity of the dye transfer image, as viewed by theobserver, and, most preferably, an agent which is aesthetically pleasingto the viewer and does not provide a background noise signal degrading,or detracting from, the information content of the image. Particularlydesirable reflecting agents will comprise pigments providing a whitebackground, for viewing the transfer image, and specifically thoseconventionally employed to provide background for reflectionphotographic prints and, especially those agents possessing the opticalproperties desired for reflection of incident radiation.

As examples of reflecting pigments adapted for employment in thepractice of the present invention, mention may be made of bariumsulfate, zinc sulfide, titanium dioxide, barium stearate, silver flake,silicates, alumina, zirconium oxides, zirconium acetyl acetate, sodiumzirconium sulfate, kaolin, mica, and the like.

A particularly preferred reflecting agent comprises titanium dioxide dueto its highly effective reflection properties. In general, in suchpreferred embodiment, titanium dioxide will be present in aconcentration effective to provide a percent reflectance of 85 will becoated at a coverage of 200 to 1,000 mgs./ft. to provide the reflectinglayer.

In general, the reflecting agents to be employed are those which remainsubstantially immobile within their respective compositions during andsubsequent to photographic processing and particularly those whichcomprise insoluble and nondiffusible inorganic pigment dispersionswithin the layer in which they are disposed.

Where desired, reflecting agent pigment may thus be distributed in wholeor in part within a processing composition permeable polymeric matrixsuch as gelatin and/or any other such polymeric matrixes as arespecifically denoted throughout the specification as suitable foremployment as a matrix binder and may be distributed in one or more ofthe film unit layers which may be separated or contiguous, opposite theimagereceiving layer from the transparent support, provided that itsdistribution and concentration is effective to provide the denoted postprocessing masking function.

the opacifying agent selected should be one exhibiting maximum spectralabsorption of radiation at the wavelengths to which the film unitsphotosensitive silver halide layer or layers are sensitive and should besubstantially immobile or nondiffusible during performance of itsradiation filtration function, in order to maintain and enhance theoptical integrity of the dispersion as a radiation filter unitfunctioning in accordance with the present invention, and to prevent itsdiffusion into and localized concentration within the reflection and/orimage-receiving layer thereby decreasing the efiiciency of thereflecting pigment dispersion as a background against which imageformation may be immediately viewed, during and subsequent to theinitial stages in the diffusion transfer processing of the film unit.Commensurate with the spectral sensitivity range of the associatedsilver halide layer or layers, the opacifying agent selected maycomprise one or more filter materials possessing absorptioncomplementary to such silver halide layers in order to provide effectiveprotection against physical fog providing radiation during processingand the selected agents should be those exhibiting major spectralabsorption during transfer image formation and will be preferablyselected for employment in the minimum concentration necessary toprovide an optical transmission density 6.0, at wavelengths at which thesilver halide layer is maximally responsive.

As examples of opacifying agents adapted for employment in the practiceof the present invention, mention may be made of opacifying pigments andopacifying dyes and mixtures of such dyes and/or pigments preferablydyes and pigments of black coloration and most preferably black pigmentssuch as carbon black, iron oxide, titanium (lII) oxide, titanium (lll)hydroxide, and the like.

Preferred opacifying agent or agents will possess the maximum opacifyingcapacity per unit weight, be photographically nondelterious andsubstantially nondiffusible during and subsequent to distribution of theprocessing composition which may contain the same. A particularlypreferred opacifying agent has been found to comprise carbon black dueto its highly efficient absorption characteristics. In general, aprocessing composition particularly desired for employment in the letteridentified embodiment will contain carbon black in a concentrationeffective, e.g., about 3 to 6 grams of carbon black dispersed in 100 cc.of water, to prevent transmission, through the distributed stratumcomprising the composition, of in excess of percent of the actinicradiation incident on the stratum.

In general, preferred agents, both opacifying and filter, are thosewhich remain immobile within their respective compositions during thesubsequent to photographic processing and particularly those whichcomprise insoluble and nondiffusible materials.

As disclosed in the previously cited patents, the liquid processingcomposition referred to for effecting multicolor diffusion transferprocesses comprises at least an aqueous solution of an alkalinematerial, for example, diethylamine, sodium hydroxide or sodiumcarbonate and the like, and preferably possessing a pH in excess of 12,and most preferably includes a viscosity-increasing compoundconstituting a film-forming material of the type which, when thecomposition is spread and dried, forms a relatively firm and relativelystable film. The preferred film-forming materials disclosed comprisehigh molecular weight polymers such as polymeric, water-soluble etherswhich are inert to an alkaline solution such as, for example, ahydroxyethyl cellulose or sodium carboxymethyl cellulose. Additionally,film-forming materials or thickening agents whose ability to increaseviscosity is substantially unaffected if left in solution for a longperiod of time are also disclosed to be capable of utilization. Asstated, the filmforming material is preferably contained in theprocessing composition in such suitable quantities as to impart to thecomposition a viscosity in excess of 100 cps. at a temperature ofapproximately 24 C. and preferably in the order of 100,000 cps. to200,000 cps. at that temperature.

In the performance of a diffusion transfer multicolor process employingfilm unit 10, the unit is exposed to radiation, actinic tophotosensitive laminate 90, incident on the laminates exposure surface.

Subsequent to exposure, film unit is processed by being passed throughopposed suitably gapped rolls 29 and 30 in order to apply compressivepressure to frangible container 21 and to effect rupture of longitudinalseal 32 and distribution of alkaline processing composition 39,optionally possessing an inorganic opacifying pigment and a pH at whichthe cyan, magenta and yellow dye developers are soluble and diffusibleas a function of the point-to-point degree of exposure of redsensitivesilver halide emulsion layer 93, greensensitive silver halide emulsionlayer 96 and bluesensitive silver halide emulsion layer 99,respectively, intermediate auxiliary layer 100 and image-receivinglaminate 101.

Alkaline processing composition 39 permeates emulsion layers 93, 96 and99 to initiate development of the latent images contained in therespective emulsions. The cyan, magenta and yellow dye developers, oflayers 92, 95 and 98, are immobilized, as a function of the developmentof their respective associated silver halide emulsions, preferablysubstantially as a result of their conversion from the reduced form totheir relatively insoluble and nondiffusible oxidized form, therebyproviding imagewise distributions of mobile, soluble and diffusiblecyan, magenta and yellow dye developer, as a function of thepoint-to-point degree of their associated emulsions exposure. At leastpart of the imagewise distributions of mobile cyan, magenta and yellowdye developer transfers, by diffusion, to dyeable polymeric layer 104 toprovide a multicolor dye transfer image to that layer which is viewableagainst the background provided by the reflecting layer 103 maskingcyan, magenta and yellow dye developer remaining associated withblue-sensitive emulsion layer 99, greensensitive emulsion layer 96 andred-sensitive emulsion layer 93. Subsequent to substantial transferimage formation, a sufficient portion of the ions comprising aqueousalkaline processing composition 39 transfer, by diffusion, throughpermeable polymeric reception layer 104, permeable spacer layer 105 topolymeric neutralizing layer 106 whereby the environmental pH of thesystem decreases as a function of neutralization to a pH at which thecyan, magenta and yellow dye developers, in the reduced form, aresubstantially nondiffusible to thereby provide a stable multicolor dyetransfer image.

The alkaline solution component of the processing composition,positioned intermediate the photosensitive element and theimage-receiving layer, thus permeates the emulsions to initiatedevelopment of the latent images contained therein. The respectiveassociated dye developers are mobilized in unexposed areas as aconsequence of the development of the latent images. This mobilizationis apparently, at least in part, due to a change in the solubilitycharacteristics of dye developer upon oxidation and especially. asregards to solubility in alkaline solutions. It may also be due in partto a tanning effect on the emulsion by oxidized developing agent, and inpart to a localized exhaustion of alkali as a result of development. Inunexposed and partially exposed areas of the emulsions, the associateddye developer is diffusible and thus provides an imagewise distributionof unoxidized dye developer dissolved in the liquid processingcomposition, as a function of the pointto-point degree of exposure ofthe silver halide emulsion. At least part of this imagewisedistributionof unoxidized dye developer is transferred, by imbibition, to asuperposed image-receiving layer or element, said transfer substantiallyexcluding oxidized dye developer. The image-receiving element receives adepthwise diffusion, from the developed emulsion, of unoxidized dyedeveloper without appreciably disturbing the imagewise distributionthereof to provide the reversed or positive color image of thedeveloped. image.

Subsequent to distribution of processing composition 39, leading endsections 20 and 23 including container 31 may be manually dissociatedfrom the remainder of the film unit, as described above.

The present invention will be further illustrated and detailed inconjunction with the following illustrative constructions which set outrepresentative embodiments and photographic utilization of the novelphotographic film units of this invention, which, however, are notlimited to the details therein set forth and are intended to beillustrative only.

Photosensitive sheet elements similar to that shown in the drawings maybe prepared, for example, by coating, in succession, on a gelatinsubbed, 5 mil. opaque cellulose triacetate film base, the followinglayers:

1. a layer of the cyan dye developer l,4-bis-(,B-

[ hydroquinonyl-a-methyl]-ethylamino )-5 ,8- dihydroxy-anthraquinonedispersed in gelatin and coated at a coverage of about mgs./ft. of dyeand about mgs./ft. of gelatin;

2. a red-sensitive gelatino-silver iodobromide emulsion coated at acoverage of about 225 mgs./ft. of silver and about 50 mgs/ft. ofgelatin;

3. A layer of the acrylic latex sold by Rohm and Haas Co., Philadelphia,Penna, U.S.A., under the trade designation AC-6l and polyacrylamidecoated at a coverage of about 150 mgs./ft. of AC-6l and about 5 mgs/ft.of polyacrylamide;

4. a layer of magenta dye developer 2-(p-[B-hydroquinonylethyl]-phenylazo)-4-isopropoxyl naphthol dispersed ingelatin and coated at a coverage of 70 mgs./ft. of dye and aboutmgs./ft. of gelatin;

5. a green-sensitive gelatino-silver iodobromide emulsion coated at acoverage of about 120 mgs./ft. of silver and 60 mgsJft. of gelatin;

6. a layer comprising the acrylic latex sold by Rohm and Haas Co. underthe trade designation Bl5 and polyacrylamide coated at a coverage ofabout 100 mgs./ft. of B-lS and about 10 mgs./ft. of polyacrylamide;

7. a layer of the yellow dye developer 4-(p-[B-hydroquinonylethyl]-phenylazo)-3-( N,nhexylcarbox-amido)- l-phenyl-5-pyrazolone and the auxiliary developer 4'-methylphenylhydroqui none dispersed in gelatin and coated at a coverage of about 50mgs/ft." of dye, about 15 mgs./ft." of auxiliary developer and 50mgs./ft. of gelatin;

8. a blue-sensitive gelatino-silver iodobromide emulsion coated at acoverage of about 75 mgs./ft. of silver and about 75 mgs./ft. ofgelatin; and

9. a layer of gelatin coated at a coverage of about 50 mgs./ft. ofgelatin.

Image-receiving sheet elements may be constructed by coating atransparent 5 mil. cellulose triacetate film base, in succession, withthe following illustrative layers:

1. a 7:3 mixture, by weight, of polyethylene/maleic acid copolymer andpolyvinyl alcohol at a coverage of about 1,400 mgs./ft. to provide apolymeric acid layer;

2. a graft copolymer of acrylamide and diacetone ac-' ylamide on apolyvinyl alcohol backbone in a molar ratio of 1:3.2:l at a coverage ofabout 800 mgs./ft. to provide a polymeric spacer layer;

3. a 2:1 mixture, by weight, of polyvinyl alcohol andpoly-4-vinylpyridine, at a coverage of about 900 mgs./ft. and includingabout 20 mgs./ft. phenyl mercapto tetrazole, to provide a polymericimagereceiving layer; and

4. a layer of titanium dioxide coated at a coverage -600 mgs./ft.titanium dioxide and 150 mgsJft. gelatin to provide a polymericreflecting layer approximately 0.15 mil. thick.

The two components thus prepared may then be assembled together in thefilm unit form shown in the drawing employing rupturable containercomprising an outer layer of lead foil and an inner liner or layer ofpolyvinyl chloride retaining an aqueous alkaline processing solutioncomprising:

Water 100 cc. Potassium hydroxide 11.2 gms. Hydroxyethyl cellulose (highviscosity) [commercially available from Hercules Powder Co., Wilmington,Del., under the trade name Natrasol 250] 3.4 gms.N-phenethyl-a-picolinium bromide 1.5 gms. Benzotriazole 1.0 gm. Titaniumdioxide 40.0 gms. Carbon black 6.0 gms.

such that, upon application of compressive pressure to a container, itscontents may be distributed, upon rupture of the containers marginalseal, between the reflecting layer and next adjacent gelatin layer.

The photosensitive composite film units may be exposed and processed bypassage of the exposed film units through appropriate pressure-applyingmembers, such as suitably gapped, opposed rolls, to effect rupture ofthe containerand distribution of its contents. During processing, themulticolor dye transfer image formation may be viewed through thetransparent cellulose triacetate layer against the titanium dioxidereflecting layer backgroun. Multicolor dye transfer image formation willbe found to be substantially completed and exhibiting the required colorbrilliance, hues, saturation and isolation, with a period ofapproximately 90 seconds. The image formation may be immediately viewedupon distribution of the processing composition by reason of theprotection against incident radiation afforded the photosensitive silverhalide emulsion layers by the compositions optical transmission densityof -6.0 density units and against the titanium dioxides effectivereflective background.

The pH and solvent concentration of the alkaline processing solutioninitially employed must possess a pH at which the dye developersemployed are soluble and diffusible. Although it has been found that thespecific pH to be employed maybe readily determined empirically for anydye developer and optical filter agent,

or group of dye developers and filter agents, most particularlydesirable dye developers are soluble at pHs above 9 and relativelyinsoluble at pHs below 9, in reduced form, and relatively insoluble atsubstantially any alkaline pH, in oxidized form, and the system can bereadily balanced accordingly for such dye developers. In addition,although as previously noted, the processing composition, in thepreferred embodiment, will include the stated film-formingviscosity-increasing agent, or agents, to facilitate spreading of thecomposition and to provide maintenance of the spread composition as astructurally stable layer of the laminate, subsequent to distribution,it is not necessary that such agent be employed as a component of thecomposition.

Neutralizing means, for example, a polymeric acid layer of the typediscussed above will be incorporated, as stated, in the film unit of thepresent invention, to provide reduction of the alkalinity of theprocessing solution from a pH at which the dyes are soluble to a pHbelow the pKa of the agent at which the dyes are substantiallynondifiusible, in order to advantageously further stabilize and optimizereflectively of the dye transfer image. ln such instance, theneutralizing layer may comprise particulate acid reacting reagentdisposed within the film unit or a polymeric acid layer, for example, apolymeric acid layer approximating 0.3 to 1.5 mils. in thickness,positioned intermediate the transparent support and image-receivinglayer, and/or the Opaque support and next adjacent emulsion/dye unitlayer, and the film unit may also contain a polymeric spacer or barrierlayer, for example, approximately 0.1 to 0.7 mil. in thickness, nextadjacent the polymeric acid layer, opposite the respective supportlayer, as previously described.

Specifically, the film units may employ the presence of a polymeric acidlayer such as, for example, of the type set forth in U. S. Pat. No.3,362,819 which, most preferably, includes the presence of an inerttiming or spacer layer intermediate the polymeric acid layer carried ona support and the image-receiving layer.

As set forth in the last-mentioned patent, the polymeric acid layer maycomprise polymers which contain acid groups, such as carboxylic acid andsulfonic acid groups, which are capable of forming salts with alkalimetals, such as sodium, potassium etc., or with organic bases,particularly quaternary ammonium bases, such as tetramethyl ammoniumhydroxide, or potentially acid-yielding groups, such as anhydrides orlactones, or other groups which are capable of reacting with bases tocapture and retain them. The acid-reacting group is, of course, retainedin the polymer layer. In the preferred embodiments disclosed, thepolymer contains free carboxyl groups and the transfer processingcomposition employed contains a large concentration of sodium and/orpotassium ions. The acid polymers stated to be most useful arecharacterized by containing free carboxyl groups, being insoluble inwater in the free acid form, and by forming water-soluble sodium and/orpotassium salts. One may also employ polymers containing carboxylic acidanhydride groups, at least some of which preferably have been convertedto free carboxyl groups prior to imbibition. While the most readilyavailable polymeric acids are derivatives of cellulose or of vinylpolymers, polymeric acids from other classes of polymers may be used. Asexamples of specific polymeric acids set forth in the application,mention may be made of dibasic acid half-ester derivatives of cellulosewhich derivatives contain free carboxyl groups, e.g., cellulose acetatehydrogen phthalate, cellulose acetate hydrogen glutarate, celluloseacetate hydrogen succinate, ethyl cellulose hydrogen succinate, ethylcellulose acetate hydrogen succinate, cellulose acetate hydrogensuccinate hydrogen phthalate; ether and ester derivatives or cellulosemodified with sulfoanhydrides, e.g., with ortho-sulfobenzoic anhydride;polystyrene sulfonic acid; carboxymethyl cellulose; polyvinyl hydro genphthalate; polyvinyl acetate hydrogen phthalate; polyacrylic acid;acetals of polyvinyl alcohol with carboxy or sulfo substitutedaldehydes, tag, m-, or pbenzaldehyde sulfonic acid or carboxylic acid;partial esters of ethylene/maleic anhydride copolymers; partial estersof methyl-vinyl ether/maleic anhydride copolymers; etc.

As previously noted, the pH of the processing composition preferably isof the order of at least 12 to 14 and the pKa of the selected opticalfilter agents will accordingly preferably be in the order of 13 orgreater. The polymer layer is disclosed to contain at least sufficientacid groups to effect a reduction in the pH of the image receiving layerfrom a pH of about 12 to 14 to a pH of at least 1 l or lower at the endof the imbibition period, and preferably to a pH of about 5 to 8 withina short time after imbibition, thus requiring, of course, that theaction of the polymeric acid be accurately so controlled as not tointerfere with either development of the negative or image transfer ofunoxidized dye developers. For this reason, the pH of the imagereceiving layer must be kept at a functional transfer level, forexample, 12 to 14 until the dye image has been formed after which the pHis reduced very rapidly to a pH below that at which dye transfer may beaccomplished, for example, at least about 1 l and preferably about pH 9to 10. Unoxidized dye developers containing hydroquinonyl developingradicals diffuse from the negative to the positive as the sodium orother alkali salt. The diffusion rate of such dye image-formingcomponents thus is at least partly a function of the alkaliconcentration, and it is necessary that the pH of the image receivinglayer remain on the order of, for example, 12 to 14 until transfer ofthe necessary quantity of dye has been accomplished. The subsequent pHreduction, in addition to its desirable effect upon image lightstability, serves a highly valuable photographic function bysubstantially terminating further dye transfer.

In order to prevent premature pH reduction during transfer processing,as evidenced, for example, by an undesired reduction in positive imagedensity, the acid groups are disclosed to be so distributed in thepolymer layer that the rate of their availability to the alkali iscontrollable, e.g., as a function of the rate of swelling of the polymerlayer which rate in turn has a direct relationship to the diffusion rateof the alkali ions. The desired distribution of the acid groups in thepolymer layer may be effected by mixing acid polymer with a polymer freeof acid groups, or lower in concentration of acid groups, and compatibletherewith, or by using only an acid polymer but selecting one having arelatively lower proportion of acid groups. These embodiments areillustrated, respectively, in the cited copending application, by (a) amixture of cellulose acetate and cellulose acetate hydrogen phthalateand (b) a cellulose acetate hydrogen phthalate polymer having a muchlower percentage of phthayl groups than the firstmentioned celluloseacetate hydrogen phthalate.

It is also there disclosed that the layer containing the polymeric acidmay contain a water-insoluble polymer, preferably a cellulose ester,which acts to control or modulate the rate at which the alkali salt ofthe polymer acid is formed. As examples of cellulose esters contemplatedfor use, mention is made of cellulose acetate, cellulose acetatebutyrate, etc. The particular polymers and combinations of polymersemployed in any given embodiment are, of course, selected so as to haveadequate wet and dry strengthand when neces sary or desirable, suitablesubcoats are employed to help the various polymeric layers adhere toeach other during storage and use. I

The inert spacer layer of the last-mentioned patent, for example, aninert spacer layer comprising polyvinyl alcohol or gelatin, acts to timecontrol the pH reduction by the polymeric acid layer. This timing is disclosed to be a function of the rate at which the alkali diffuses throughthe inert spacer layer. It is there stated to have been found that thepH does not drop until the alkali has passed through the spacer layer,i.e., the pH is not reduced to any significant extent by the merediffusion into the interlayer, but the pH drops quite rapidly once thealkali-diffuses through the spacer layer.

As disclosed in aforementioned U. S. Pat. No. 3,362,819, the presence ofan inert spacer layer was found to be effective in evening out thevarious reaction rates over a wide range of temperatures, for example,by preventing premature pH reduction when imbibition is effected attemperatures above room temperature, for example, at to F. By providingan inert spacer layer, that application discloses that the rate at whichalkali is available for capture in the polymeric acid layer becomes afunction of the alkali diffusion rates.

However, as disclosed in U. S. Pat. No. 3,455,686 preferably theaforementioned rate at which the cations of the alkaline processingcomposition, i.e., alkali ions, are available for capture in thepolymeric acid layer should be decreased with increasing transferprocessing temperatures in order to provide diffusion transfer colorprocesses relatively independent of positive transfer image variationsover an extended range of ambient temperatures.

Specifically, it is there stated to have been found that the diffusionrate of alkali through a permeable inert polymeric spacer layerincreases with increased processing temperature to the extent, forexample, that at relatively high transfer processing temperatures, thatis, transfer processing temperatures above approximately 80 F., apremature decrease in the pH of the transfer processing compositionoccurs due, at least in part, to the rapid diffusion of alkali from thedye transfer environment and its subsequent neutralization upon contactwith the polymeric acid layer. This was stated to be especially true ofalkali traversing an inert spacer layer possessing permeability toalkali optimized to be effective with the temperature range of optimumtransfer processing. Conversely, at temperatures below the optimumtransfer processing range, for example, temperatures below approximately40 F., the lastmentioned inert spacer layer was disclosed to provide aneffective diffusion barrier timewise preventing effective traverse ofthe inert spacer layer by alkali having temperature depressed diffusionrates and to result in maintenance of the transfer processingenvironments high pH for such an extended time interval as to facilitateformation of transfer image stain and its resultant degradation of thepositive transfer images color definition.

It is further stated in the last-mentioned U. S. Pat. No. 3,455,686 tohave been found, however, that if the inert spacer layer of theprint-receiving element is replaced by a spacer layer which comprises apermeable polymeric layer exhibiting permeability inversely dependent ontemperature, that is, a polymeric filmforming material which exhibitsdecreasing permeability to solubilized alkali derived cations such asalkali metal and quaternary ammonium ions under conditions of increasingtemperature, that the positive transfer image defects resultant from theaforementioned overextended pH maintenance and/or premature pH reductionare obviated.

As examples of polymers which were disclosed to exhibit inversetemperature-dependent permeability to alkali, mention may be made of:hydroxypropyl polyvinyl alcohol, polyvinyl methyl ether, polyethyleneoxide, polyvinyl oxazolidone, hydroxypropyl methyl cellulose, isopropylcellulose, partial acetals of polyvinyl alcohol such as partialpolyvinyl butyral, partial polyvinyl formal, partial polyvinyl acetal,partial polyvinyl propional, and the like.

The last-mentioned specified acetals of polyvinyl were stated togenerally comprise saturated aliphatic hydrocarbon chains of a molecularweight of at least 1,000, preferably of about 1,000 to 50,000,possessing a degree of acetalation within about to 30 percent, 10 to 30percent, to 80 percent, and 10 tp 40 percent, of the polyvinyl alcoholstheoretical polymeric hydroxy groups, respectively, and including mixedacetals where desired.

Where desired, a mixture of the polymers may be employed, for example, amixture of hydroxypropyl methyl cellulose and partial polyvinyl butyral.

Employment of the detailed and preferred film units of the presentinvention, according to the herein described color diffusion transferprocess, specifically provides for the production of a highly stabletransfer image accomplished, at least in part, by in-process adjustmentof the environmental pH concentration from a pH concentration at whichdye transfer is inoperative subsequent to substantial transfer imageformation. The stable color transfer image is obtained irrespective ofthe fact that the film unit is maintained as an integral laminate unitduring processing, viewing and storage of the reflection print. Themulticolor transfer images may be provided over an extended processingtemperature range which exhibit desired maximum and minimum dye transferimage densities; yellow, magenta and cyan dye saturation; red, green andblue hues; and color separation and customer utilization of the unit.

The dimensionally stable support layers referred to may comprise any ofthe various types of conventional opaque and transparent rigid orflexible materials possessing the requisite liquid impermeability andvapor transmissivity denoted above, and may comprise polymeric films ofboth synthetic types and those derived from naturally occurringproducts. Particularly suitable materials include aqueous alkalinesolution impermeable, water vapor permeable, flexible polymericmaterials such as vapor permeable polymeric films derived from ethyleneglycol terephthalic acid, vinyl chloride polymers; polyvinyl acetate;polyamides; polymethacrylic acid methyl and ethyl esters; cellulosederivatives such as cellulose, acetate, triacetate, nitrate, propionate,butyrate, acetate-propionate, or acetatebutyrate; alkaline solutionimpermeable, water vapor permeable papers; crosslinked polyvinylalcohol; regenerated cellulose; and the like.

As examples of materials, for use as the imagereceiving layer, mentionmay be made of solution dyeable polymers such as nylon as, for example,N- methoxymethyl polyhexamethylene adipamide; partially hydrolyzedpolyvinyl acetate; polyvinyl alcohol with or without plasticizers;cellulose acetate with filler as, for example, one-half celluloseacetate and one-half oleic acid; gelatin; and other materials of asimilar nature. Preferred materials comprise polyvinyl alcohol orgelatin containing a dye mordant such as poly-4- vinylpyridine, asdisclosed in U. S. Pat. No. 3,148,061, issued Sept. 8, 1964.

It will be noted that the liquid processing composition employed maycontain an auxiliary or accelerating developing agent, such asp-methylaminophenol, 2,4- diamino-phenol, p-benzylaminophenyl,hydroquinone, toluhydroquinone, phenylhydroquinone,4-methylphenylhydroquinone, etc. It is also contemplated to employ aplurality of auxiliary or accelerating developing agents, such as a3-pyrazolidone developing agent and a benzenoid developing agent, asdisclosed in U. S. Pat. No. 3,039,869, issued June 19, 1962. As examplesof suitable combinations of auxiliary developing agents, mention may bemade of l-phenyl-3-pyrazolidone in combination with p-benzylaminophenoland l-phenyl- 3-pyrazolidone in combination with2,5-bisethylenimino-hydroquinone. Such auxiliary developing agents maybe employed in the liquid processing composition or they may beinitially incorporated, at least in part, in any one or more of thesilver halide emulsion strata, the strata containing the dye developers,the interlayers, the overcoat layer, the image-receiving layer, or inany other auxiliary layer, or layers, of the film unit. It may be notedthat at least a portion of the dye developer oxidized during developmentmay be oxidized and immobilized as a result of a reaction, e.g., anenergytransfer reaction, with the oxidation product of an oxidizedauxiliary developing agent, the latter developing agent being oxidizedby the development of exposure silver halide. Such a reaction ofoxidized developing agent with unoxidized dye developer would regeneratethe auxiliary developing agent for further reaction with the exposedsilver halide.

In addition, development may be effected in the presence of an oniumcompound, particularly a quaternary ammonium compound, in accordancewith the processes disclosed in U. S. Pat. No. 3,173,786, issued Mar.16, 1965.

It will be apparent that the relative proportions of the agents of thediffusion transfer processing composition may be altered to suit therequirements of the operator. Thus, it is within the scope of thisinvention to modify the herein described developing compositions by thesubstitution of preservatives, alkalies, etc., other than thosespecifically mentioned, provided that the pH of the composition isinitially at the first pH and solvent concentration required. Whendesirable, it is also contemplated to include, in the developingcomposition, components such as restrainers, accelerators, etc.Similarly, the concentration of various components may be varied over awide range and when desirable adaptable components may be disposed inthe photosensitive element, prior to exposure, in a separate permeablelayer of the photosensitive element and/or in the photosensitiveemulsion.

In all examples of this specification, percentages of components aregiven by weight unless otherwise indicated.

As additional examples of synthetic, film-forming, permeable polymersparticularly adapted to retain dispersed dye developer, mention may bemade of nitrocarboxymethyl cellulose, as disclosed in U. S. Pat. No.2,992,104; an acylamidobenzene sulfo ester of a partial sulfobenzal ofpolyvinyl alcohol, as disclosed in U. S. Pat. No. 3,043,692; polymers ofN-alkyl-a,[-3- unsaturated carboxamides and copoly-mers ofN-alkyl-a,B-carboxamides with N-hydroxyalkyl-a,B- unsaturatedcarboxamides, as disclosed in U. S. Pat. No. 3,069,263; copolymers ofvinylphthalimide and a,B-unsaturated carboxylic acids, as disclosed inU. 8. Pat. No. 3,061,428; copolymers of N-vinylpyrrolidones anda,,B-unsaturated carboxylic acidsand terpolymers of N-vinylpyrrolidones,call-unsaturated carboxylic acids and alkyl esters of a,B-unsaturatedcarboxylic acids, as disclosed in U. S. Pat. No. 3,044,873; copolymersof N,N-dialkyl-a,B-unsaturated carboxamides with a,B-unsaturatedcarboxylic acids, the corresponding amides of such acids, and copolymersof N-aryl-and N-cycloalkyl-a,,B-unsaturated carboxamides witha,B-unsaturated carboxylic acids, as disclosed in U. S. Pat. No.3,069,296; and the like.

ln addition to conventional techniques for the direct dispersion of aparticulate solid material in a polymeric, or colloidal, matrix such asball-milling and the like techniques, the preparation of the dyedeveloper dis persion may also be obtained by dissolving the dye in anappropriate solvent, or mixture of solvents, and the resultant solutiondistributed in the polymeric binder, with optional subsequent removal ofthe solvent, or solvents, employed, as, for example, by vaporizationwhere the selected solvent, or solvents, possesses a sufficiently lowboiling point or washing where the selected solvent, or solvents,possesses a sufficiently high differential solubility in the washmedium, for example, water, when measured against the solubility of theremaining composition components, and/or obtained by dissolving both thepolymeric binder and dye in a common solvent.

For further detailed treatment of solvent distribution systems of thetypes referred to above, and for an extension compilation of theconventional solvents traditionally employed in the art to effectdistribution of photographic color-providing materials in polymericbinders, specifically for the formation component layers of photographicfilm units, reference may be made to U. S. Pat. Nos. 2,269,158;2,322,027; 2,304,939; 2,304,940; 2,801,171; and the like.

Although the invention has been discussed in detail throughout employingdye developers, the preferred image-providing materials, it will bereadily recognized that other, less preferred, image-providing materialsmay be substituted in replacement of the preferred dye developers in thepractice of the invention. For example, there may be employed dyeimage-forming materials wherein color diffusion transfer processes aredescribed which employ color coupling techniques ,comprising, at leastin part, reacting one or more color developing agents and one or morecolor formers or couplers to provide a dye transfer image to asuperposed image-receiving layer wherein color diffusion transferprocesses are described which employ the imagewise differential transferof complete dyes by the mechanisms therein described to provide atransfer dye image to a contiguous image-receiving layer, and thusincluding the employment of image-providing materials in whole or inpart initially insoluble or nondiffusible as disposed in the film unitwhich diffuse during processing as a direct or indirect function ofexposure.

For the production of the photosensitive gelatino silver halideemulsions employed to provide the film unit, the silver halide crystalsmay be prepared by reacting a water-soluble silver salt, such as silvernitrate, with at least one water-soluble halide, such as ammonium,potassium or sodium bromide, preferably together with a correspondingiodide, in an aqueous solution of a peptizing agent such as a colloidalgelatin solution; digesting the dispersion at an elevated temperature,to provide increased crystal growth; washing the resultant water-solublesalts by chilling the dispersion, noodling the set dispersion, andwashing the noodles with cold water, or alternatively, employing any ofthe various flocc systems, or procedures, adapted to effect removal ofundesired components, for example, the procedures described in U. S.Pat. Nos. 2,614,928; 2,614,929; 2,728,662; and the like; after-ripeningthe dispersion at an elevated temperature in combination with theaddition of gelatin and various adjuncts, for example, chemicalsensitizing agents of U. S. Pat. Nos. 1,574,944; 1,623,499; 2,410,689;2,597,856; 2,597,915; 2,487,850; 2,518,698; 2,521,926; and the like; allaccording to the traditional procedures of the art, as described inNeblette, C. 3., Photography Its Materials and Processes, 6th Ed., 1962.

Optical sensitization of the emulsions silver halide crystals may beaccomplished by contact of the emulsion composition with an effectiveconcentration of the selected optical sensitizing dyes dissolved in anappropriate dispersing solvent such as methanol, ethanol, acetone,water, and the like; all according to the traditional procedures of theart, as described in Hammer, F. M., The Cyanine Dyes and RelatedCompounds.

Additional optional additives, such as coating aids, hardeners,viscosity-increasing agents, stabilizers, preservatives, and the like,for example, those set forth hereinafter, also may be incorporated inthe emulsion formulation, according to the conventional procedures knownin the photographic emulsion manufacturing art.

The photoresponsive material of the photographic emulsion will, aspreviously described, preferably comprise a crystal of silver, forexample, one or more of the silver halides such as silver chloride,silver iodide, silver bromide, or mixed silver halides such as silverchlorobromide, silver chloroiodobromide or silver iodobromide, ofvarying halide ratios and varying silver concentrations.

As the binder for the respective emulsion strata, the aforementionedgelatin may be, in whole or in part, replaced with some other colloidalmaterial such as albumin; casein; or zein; or resins such as a cellulosederivatives, as described in U. S. Pat. Nos. 2,322,085 and 2,327,808;polyacrylamides, as described in U. S. Pat. No. 2,541,474; vinylpolymers such as described in an extensive multiplicity of readilyavailable U. S. and foreign patents.

the photosensitive silver halide emulsions employed will be emulsionsadapted to provide a Diffusion Transfer Process Exposure Index 50, whichIndex indicates the correct exposure rating of a diffusion transfercolor process at which an exposure meter, calibrated to the ASA ExposureIndex, must be set in order that it give correct exposure data forproducing color transfer prints of satisfactorily high quality. TheDiffusion Transfer Process Exposure Index is based on a characteristicl-I&D curve relating original exposure of the photosensitive silverhalide emulsions to the respective curve densities forming the resultanttransfer image. Thus, the Diffusion Transfer Exposure Index is based onthe exposure to which the photosensitive silvelr halide emulsions, foruse in color diffusion transfer. processes, must be subjected in orderto obtain an acceptable color transfer image by that process and is adirect guide to the exposure setting to be entered in a camera in orderto obtain proper exposure of the film uhit.

Although the preceding description of the invention has been couched interms of the preferred photosensitive component construction wherein atleast two selectively sensitized photosensitive strata are in contiguouscoplanar relationship and, specifically, in terms of the preferredtripack type structure comprising a redsensitive silver halide emulsionstratum, a greensensitive silver halide emulsion stratum and abluesensitive silver halide emulsion stratum having associatedtherewith, respectively a cyan dye develo er, a magenta dye developerand a yellow dye developer, the photosensitve component of the film unitmay comprise at least two sets of selectively sensitized minutephotosensitive elements arranged in the form of a photosensitive screenwherein each of the minute photosensitve elements has associatedtherewith, for example, an appropriate dye developer in or behind itsrespective silver halide emulsion portion. In general, a suitablephotosensitive screen will comprise m'inute red-sensitized emulsionelements, minute greensensitized emulsion elements and minutejbluesensitized emulsion elements arranged in side-by-side relationshipin a screen pattern and having associated therewith, respectively, acyan, a magenta and a yellow dye developer.

The present invention also includes the employment ofa black dyedeveloper and the use ofa mixture of dye developers adapted to provide ablack-and-white transfer image, for example, the employment of dyedevelopers of the three subtractive colors in an appropriate mixture inwhich the quantities of the dye developers are proportioned such thatthe colors combine to provide black.

Where in the specification, the expression positive image has been used,this expression should not be interpreted in a restrictive sense sinceit is used primarily for purposes of illustration, in that it definesthe image produced on the image-carrying layer as being reversed, in thepositive-negative sense, with respect to the image in the photosensitiveemulsion layers. As an example of an alternative meaning for positiveimage, assume that the photosensitive element is exposed to actiniclight through a negative transparency. In this case, the latent image inthe photosensitive emulsion layers will be a positive and the dye imageproduced on the image-carrying layer will be a negative. The expressionpositive image" is intended to cover such an image produced on theimage-carrying layer.

It will be recognized that, by reason of the preferred film unitsstructural parameters, the transfer image formed upon direct exposure ofthe film unit to a selected subject and processing, will be ageometrically reversed image of the subject. Accordingly, to providetransfer image formation geometrically nonreversed, exposure of suchfilm unit must be accomplished through an image reversing opticalsystem.

In addition to the described essential layers, it will be recognizedthat the film unit may also contain one or more subcoats or layers,which, in turn, may contain one or more additives such as plasticizers,intermediate essential layers for the purpose, for example, of improvingadhesion, and that any one or more of the described layers may comprisea composite of two or more strata of the same, or different, componentsand which may be contiguous, or separated from, each other, for example,two or more neutralizing layers or the like, one of which may bedisposed intermediate the cyan dye image-forming component retaininglayer and the dimensionally stable opaque layer.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

I claim:

1. A photographic film unit for the production of a color photographicreflection print by diffusion transfer processing and adapted to beprocessed subsequent to photo-exposure by passage intermediate a pair ofjuxtaposed pressure-applying members, which film unit comprises firstand second sheet elements affixed transverse a leading end section, saidfirst sheet'comprising an opaque support carrying on one surfacephotosensitive silver halide having associated therewith a diffusiontransfer process dye image-providing material, said second sheetcomprising a transparent support carrying on one surface, in order, adiffusion transfer image-receiving layer and a dye image-providingmaterial permeable reflecting layer, at least one of said first andsecond sheets additionally carrying on the surface of said sheetintermediate the leading edge of said first sheet and said second sheetrupturable container means retaining a fluid processing composition fordistribution intermediate said first and second sheets upon applicationof pressure to said container means, said second sheet adapted to besuperposed contiguous the surface of said first sheet with saidphotosensitive silver halide and said reflecting layer intermediate saidopaque and said transparent supports and an opacifying agent disposedintegral with said reflecting layer or as a layer on the surface of saidreflecting layer opposite said transparent support or in said fluidprocessing composition.

2. A photographic film unit as defined in claim 1 wherein the trailingend section of said rupturable container is spaced from the leading edgesection of said photosensitive silver halide on said first sheet andsaid container is adapted to release said fluid processing compositionat said trailing end upon application of compressive pressure to saidcontainer, said film unit additionally including a sheet extendingtransverse and affixed each lateral edge section of said first sheetpossessing a leading edge section affixed overlying said trailing endsection of said container and a trailing edge section of said sheetaffixed contiguous said leading edge section of said photosensitiveelement providing thereby a conduit for transfer of said fluidprocessing composition from said container to said photosensitiveelement.

3. A photographic film unit as defined in claim 1 wherein said firstsheet element includes a trailing end section extending rearward of thetrailing edge of said photosensitive element adapted to be maintained insuperposed relationship with the trailing edge section of said secondsheet during processing of said film unit to retain, intermediate saidopposed trailing edge sections, processing composition extruded at thetrailing edge of said photosensitive element.

4. A photographic film unit as defined in claim 3 including a sheetelement affixed at its trailing end section to a leading end section ofone of said first and second sheet elements.

5. A photographic film unit as defined in claim 1 wherein saidopacifying agent is disposed in a layer carried on said second sheetcontiguous the surface of said reflecting layer opposite saidtransparent support.

6. A photographic film unit as defined in claim 1 wherein saidreflecting layer comprises titanium dioxide disposed in a polymericmatrix permeable to processing composition solubilized dyeimage-providing material.

7. A photographic film unit as defined in claim 1 wherein saidopacifying agent is carbon black.

8. A photographic film unit as defined in claim 1 wherein said fluidprocessing composition possesses a first pH at which the dyeimage-providing material is processing composition diffusible as afunction of its associated photo-sensitive silver halides exposure toincident actinic radiation and including means for converting,subsequent to substantial diffusion of solubilized dye image-providingmaterial to said diffusion transfer image-receiving layer, the pH of thefilm? from said first pl-l to a second pH at which a dye transfer imageprovided by said dye image-providing material exhibits increasedstability.

9. A photographic film unit as defined in claim 8 wherein said dyeimage-providing material comprises a dye which is a silver halidedeveloping agent soluble and diffusible in an aqueous alkalineprocessing composition at the first pH and substantially nondiffusibleat a second pH lower than the first pH and said means for convertingsaid pH of said film unit are adapted to reduce said processingcomposition from said first pH to said second pH subsequent tosubstantial dye transfer image formation. 1

10. A photographic film unit as defined in claim 1 including, carried onsaid opaque support, at least two selectively sensitized silver halidelayers each having a dye image-providing material adapted to provide dyeimage predetermined color as a function of the photoexposure of itssilver halide layer.

11. A photographic film unit as defined in claim 10 wherein each of theselectively sensitized silver halide emulsion layers possessespredominant spectral sensitivity to separate regions of the spectrum andthe dye image-providing material associated with each of said silverhalide emulsion layers is adapted to provide a dye transfer imagepossessing a spectral absorption range subsequent to processingsubstantially complementary to the predominant sensitivity image of itsassociated emulsion layer.

12. A photographic film unit as defined in claim 11 wherein thereflecting layer includes an inorganic lightreflecting pigment.

13. A photographic film unit as defined in claim 8 wherein said fluidprocessing composition is an aqueous alkaline composition and said meansfor converting the pH of said film unit comprise an acidic polymericlayer disposed intermediate said transparent support and image-receivinglayer or said opaque support and said photosensitive silver halide.

14. A photographic film unit as defined in claim 13 wherein said firstsheet includes, as essential layers, in sequence, a dimensionally stablealkaline solution impermeable opaque support; a red-sensitive silverhalide emulsion layer having associated therewith cyan dye; agreen-sensitive silver halide emulsion layer having associated therewithmagenta dye; a blue-sensitive silver halide emulsion layer havingassociated therewith yellow dye, each of the cyan, magenta, and yellowdyes being silver halide developing agents and being soluble anddiffusible, in alkali, at a first pH; said second sheet includes analkaline solution permeable layer comprising titanium dioxide; analkaline solution permeable and dyeable polymeric layer; an acidicpolymeric layer adapted to effect reduction of a processing compositionhaving the first pH at which the cyan, magenta and yellow dyes aresoluble and diffusible to a second pH at which the dyes aresubstantially nondiffusible; and a dimensionally stable alkalinesolution impermeable transparent support; and said rupturable containermeans retain an aqueous alkaline processing composition having the firstpH and containing substantially uniformly disposed therein carbon blacksubstantially nondiffusible from said processing composition, saidcarbon black taken together with said titanium dioxide present in aquantity sufficient, upon distribution of the aqueous alkalineprocessing composition possessing the first pH as a layer intermediatethe titanium dioxide layer and the blue-sensitive silver halide emulsionlayer, to prevent exposure of said silver halide emulsion layers byradiation incident on said transparent support.

15. A photographic film unit as defined in claim 14 wherein said carbonblack is disposed, prior to distribution of said processing composition,in an alkaline solution permeable layer contiguous the surface of saidtitanium dioxide layer opposite said transparent support.

2. A photographic film unit as defined in claim 1 wherein the trailingend section of said rUpturable container is spaced from the leading edgesection of said photosensitive silver halide on said first sheet andsaid container is adapted to release said fluid processing compositionat said trailing end upon application of compressive pressure to saidcontainer, said film unit additionally including a sheet extendingtransverse and affixed each lateral edge section of said first sheetpossessing a leading edge section affixed overlying said trailing endsection of said container and a trailing edge section of said sheetaffixed contiguous said leading edge section of said photosensitiveelement providing thereby a conduit for transfer of said fluidprocessing composition from said container to said photosensitiveelement.
 3. A photographic film unit as defined in claim 1 wherein saidfirst sheet element includes a trailing end section extending rearwardof the trailing edge of said photosensitive element adapted to bemaintained in superposed relationship with the trailing edge section ofsaid second sheet during processing of said film unit to retain,intermediate said opposed trailing edge sections, processing compositionextruded at the trailing edge of said photosensitive element.
 4. Aphotographic film unit as defined in claim 3 including a sheet elementaffixed at its trailing end section to a leading end section of one ofsaid first and second sheet elements.
 5. A photographic film unit asdefined in claim 1 wherein said opacifying agent is disposed in a layercarried on said second sheet contiguous the surface of said reflectinglayer opposite said transparent support.
 6. A photographic film unit asdefined in claim 1 wherein said reflecting layer comprises titaniumdioxide disposed in a polymeric matrix permeable to processingcomposition solubilized dye image-providing material.
 7. A photographicfilm unit as defined in claim 1 wherein said opacifying agent is carbonblack.
 8. A photographic film unit as defined in claim 1 wherein saidfluid processing composition possesses a first pH at which the dyeimage-providing material is processing composition diffusible as afunction of its associated photo-sensitive silver halide''s exposure toincident actinic radiation and including means for converting,subsequent to substantial diffusion of solubilized dye image-providingmaterial to said diffusion transfer image-receiving layer, the pH of thefilm from said first pH to a second pH at which a dye transfer imageprovided by said dye image-providing material exhibits increasedstability.
 9. A photographic film unit as defined in claim 8 whereinsaid dye image-providing material comprises a dye which is a silverhalide developing agent soluble and diffusible in an aqueous alkalineprocessing composition at the first pH and substantially nondiffusibleat a second pH lower than the first pH and said means for convertingsaid pH of said film unit are adapted to reduce said processingcomposition from said first pH to said second pH subsequent tosubstantial dye transfer image formation.
 10. A photographic film unitas defined in claim 1 including, carried on said opaque support, atleast two selectively sensitized silver halide layers each having a dyeimage-providing material adapted to provide dye image predeterminedcolor as a function of the photoexposure of its silver halide layer. 11.A photographic film unit as defined in claim 10 wherein each of theselectively sensitized silver halide emulsion layers possessespredominant spectral sensitivity to separate regions of the spectrum andthe dye image-providing material associated with each of said silverhalide emulsion layers is adapted to provide a dye transfer imagepossessing a spectral absorption range subsequent to processingsubstantially complementary to the predominant sensitivity image of itsassociated emulsion layer.
 12. A photographic film unit as defined inclaim 11 wherein the reflecting layer includes an inorganiclight-reflecting pigment.
 13. A photographic film unit as defined inclaim 8 wherein said fluid processing composition is an aqueous alkalinecomposition and said means for converting the pH of said film unitcomprise an acidic polymeric layer disposed intermediate saidtransparent support and image-receiving layer or said opaque support andsaid photosensitive silver halide.
 14. A photographic film unit asdefined in claim 13 wherein said first sheet includes, as essentiallayers, in sequence, a dimensionally stable alkaline solutionimpermeable opaque support; a red-sensitive silver halide emulsion layerhaving associated therewith cyan dye; a green-sensitive silver halideemulsion layer having associated therewith magenta dye; a blue-sensitivesilver halide emulsion layer having associated therewith yellow dye,each of the cyan, magenta, and yellow dyes being silver halidedeveloping agents and being soluble and diffusible, in alkali, at afirst pH; said second sheet includes an alkaline solution permeablelayer comprising titanium dioxide; an alkaline solution permeable anddyeable polymeric layer; an acidic polymeric layer adapted to effectreduction of a processing composition having the first pH at which thecyan, magenta and yellow dyes are soluble and diffusible to a second pHat which the dyes are substantially nondiffusible; and a dimensionallystable alkaline solution impermeable transparent support; and saidrupturable container means retain an aqueous alkaline processingcomposition having the first pH and containing substantially uniformlydisposed therein carbon black substantially nondiffusible from saidprocessing composition, said carbon black taken together with saidtitanium dioxide present in a quantity sufficient, upon distribution ofthe aqueous alkaline processing composition possessing the first pH as alayer intermediate the titanium dioxide layer and the blue-sensitivesilver halide emulsion layer, to prevent exposure of said silver halideemulsion layers by radiation incident on said transparent support.
 15. Aphotographic film unit as defined in claim 14 wherein said carbon blackis disposed, prior to distribution of said processing composition, in analkaline solution permeable layer contiguous the surface of saidtitanium dioxide layer opposite said transparent support.